Vertically adjustable scaffold construction



June 6, 1961 G. w. BOHN 2,987,297

VERTICALLY ADJUSTABLE SCAFFOLD CONSTRUCTION Filed Aug. 24, 1955 2Sheets-Sheet 1 42 Fig.4

Glen W. Balm INVEN TOR.

Mm BY y a% June 6, 1961 G. w. BOHN VERTICALLY ADJUSTABLE SCAFFOLDCONSTRUCTION Filed Aug. 24, 1955 2 Sheets-Sheet 2 A 's 0 m l/ N P 8 4 0M M I 8 a l i 0 4 win 10 2 w? M 3 m M A];

Glen W. Balm United States Patent 2,987,297 VERTICALLY ADJUSTABLESCAFFOLD CONSTRUCTION Glen W. Bolm, Mount Horeb, Wis. Filed Aug. 24,1955, Ser. No. 530,369 11 Claims. (Cl. 254-4) 'to aceiling cr'otherlocation.

A further object of the invention is to provide a scaffold constructionin accordance with the foregoing object "in which there shall beprovided a simple, sturdy and highly serviceable means for verticallyand adjustably positioning a platform at various desired elevations.

Yet another object of the invention is to provide a scaffoldconstruction having improved brace means where by the scaffold may berigidly braced in position against sway or tilting, and this despite anyirregularities in the surfa'ce'upon'which the scaffold is mounted; andwhereby the brace means may be easily and adjustably lowered into anoperative position or lifted into an inoperative position by anactuating means from an'upper portion of the scaffold.

A still further important object of the invention is to provide animproved scafiold construction wherein a pair 'of leg assemblies areconnected together in a rigid improved manner and by a member which alsosupports the flexible elevating means.

A still further object of the invention is to provide 'ascafiold'construction in accordance with the above mentioned objects inwhich a novel support construction is provided facilitating a workmansuse of the scaffold and also serving to assist in rigidly uniting andbracing the two leg assemblies of the same.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part thereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a top plan view of a preferred embodiment of a scafiold inaccordance with the principles of this invention;

FIGURE 2 is an end elevational view taken from the left end of FIGURE 1,a part of the scaffold elevating means being broken away;

FIGURE 3 is a sideelevational View taken from the right end of FIGURE 2,parts being broken away and shown in vertical section and showing theplatform in its lowered position;

FIGURE 4 is a detail view taken upon an enlarged scale in verticaltransverse section substantially upon-the plane indicated by the sectionline 4-4 of FIGURE 3 and showing certain details of the platformelevating mechanism;

FIGURE 5 is a horizontalsectional view taken substantially upon theplane indicated by the section line 5-5 of FIGURE 3;

FIGURE 6 is a detail view taken substantially upon the plane indicatedby the section line 6-6 of FIGURE 1 1 showing the manner in whichanother longitudinal beam is detachably secured to one of the legassemblies for rigidly uniting the latter; and

FIGURE 7 is a further detail view taken substantially upon the planeindicated by the section line 7-7 of FIG- URE 2 and showing the mannerin which the foot board is adapted to embrace a rung of an end assemblyand assist in rigidly uniting the two end assemblies of the base.

In the accompanying drawings, which illustrate merely by way ofexemplification of the principles of the invention, one suitableembodiment of the apparatus in accordance with the same, it will be seenthat there is provided a base indicated generally by the numeral 10 andupon which is mounted for adjustable vertical elevation, a plat formindicated generally by the numeral 12. As shown more clearly in FIGURES2 and 3, the base 10 consists of a pair of end assemblies, each of whichis a form of ladder. Thus, each end assembly includes a pair of siderails 14 between which are rigidly connected a plurality of verticallyspaced rungs 16. The side rails are preferably of a tubular constructionand the rungs, as shown in the detail view'of FIGURE 7, may be of squarecrosssection and may be either hollow or solid, as desired. In theirlower ends the side rails 14 of the end assemblies are provided withcasters 18 whereby the entire scaffold is. rendered easily mobile toposition the same at any desired location.

At theupper end of the leg assemblies of the scaffold, there is provideda'horizontally extending beam' 20 which is preferably an angle ironmember, as shown in the detail views of FIGURES 4 and 6, and as will bealso apparent from FIGURE 2. At its opposite ends, the

beam 20 is provided with a pair of depending cylindrical projections orpins 22, see FIGURE 6, which are adapted to be seated in sockets formedby the upper ends of the tubular side rails 14. The beam 20 thusprovides a connecting member or connecting means for rigidly uniting thetwo end assemblies into a unified base. To assist inrigidly connectingthe end assemblies together, there are; also provided suitablediagonally disposed bracing or tie rods 24, as shown .in FIGURE 3. Theseconnect theupper portion of one leg assembly with the lower portion ofthe other leg assembly at what may be termed the back or closed side ofthe base, this being the side he neath the horizontal beam 20.

There is also provided a foot board 36 which serves: the dual functionsof rigidifying the connection of the two leg assemblies into the baseand also provides a walk for Workmen'when handling the articles carriedby the platform and when the latter is in a raised position. The footboard, as shown in FIGURE 7, is provided adjacent each of its ends andon the underside of the same with sets. of angle iron members 32 and 34.These angle iron members may be bolted to the board and welded to eachother and have their vertical depending flanges spaced from each other adistance to snugly receive a rung 16 therebetween. Consequently, whenthe foot board is placed in vertically adjusted position upon the legassemblies, as by placing the same upon a predetermined pair of rungs,the sets of angle iron members at each end of the foot board willembrace the corresponding rung and thus rigidly lock the two legassemblies together.

Referring next primarily to FIGURES 24, it will be seen that the meansfor supporting and vertically adjusting the platform assembly 12consists of a pair of vertically slidable telescoping outer and innermembers 40 and '42, respectively. The member 40' at its' upper end isrigidly secured to the vertical depending flange of the horizontal beam20 at substantially the midportion of the same, as by welding or thelike, this being indicated at 44 in FIGURE 5. It will be understood thatany other suitable means may be provided for fastening the member .40thereto. Adjacent its lower end, a brace means in the form of a strapconstituting a bracket 46, see FIGURE 4, is provided, the same beingsecured as by a wing nut and bolt 48 to a lower portion of the outertelescoping 'and extends beyond both ends of the same. however, at itslower end, the member 42 is provided upon a bevel, as indicated indotted lines at 50 in FIG- URE 4, and also as shown in FIGURE 2. Theinner telescoping member 42, which may be either hollow or solid, isslidably received within the outer member 40 Preferably,

with an opening or socket 52 in which is received the upper end of anL-shaped member 54. The latter is rigidly secured in the socket in anysuitable manner. The

horizontally projecting portion of the member 54 constitutes a guidemember which is adapted to be received in a guide slot 56, see FIGURE 3,which opens from the lower end of the outer member 40 and extends aconsiderable length upwardly in the same. The lower end of the guideslot is positioned at the highest portion of the beveled surface 50previously mentioned.

As the inner member 42 is raised, the member 54 projecting therefromwill be guided by the inclined edge 50 to enter the lower end of theguide slot, and upon further upward movement of the inner section of thetelescoping assembly, will travel upwardly in guided relation to thelongitudinal slot 56.

Means are provided for lifting the inner member and the platform carriedthereby to vertically adjusted positions. For this purpose, as will bebest apparent from FIGURES 3, 4 and 5, there is provided a mountingbracket 60 welded or otherwise secured to the outer member 40 adjacentthe upper end of the latter and a crankshaft 62 is mounted in thisbracket to constitute a winch or Windlass, a cable 64 being attachedthereto. The other end of this cable, as shown best in FIGURE 4, issecured to an eye 66 at the outer end of the horizontally projecting armof the member 54. It will thus be apparent that by manipulating thewinch, vertical sliding movement may be imparted to the inner member 42,and the latter will be guided during its upward and downward travel inthe outer member 40 by engagement with the horizontally projecting armof the member 54 in the guide slot 56 previously mentioned.

In order to lock the telescoping members, and the platform carriedthereby, in vertically adjusted position, there is provided, as shownbest in FIGURE 4, a locking ratchet in the form of a ratchet wheel 68attached to one end of the crankshaft 62, and which cooperates with apivoted ratchet or pawl 70 which is pivoted to the bracket 60 and isyieldingly urged, as by a spring 72, into engagement with the ratchetwheel. Thus, once the telescoping sections have been adjusted by meansof the winch, the spring urged ratchet assembly will maintain them inadjusted position.

At its upper end, the inner telescoping member 42 is provided with adiametrically reduced portion or extremity 80. Preferably, thisextremity is externally screw threaded, as at 82, for reception in aninternally threaded nipple or socket 84 which is secured to theunderside of a platform 86 forming a part of the platform assembly 12.In order to reinforce and strengthen the latter, the underside of theplatform is provided with a pair of longitudinally extending, laterallyspaced angle iron members 88 between which the nipple 84 is placed andto which it may be secured, as by welding or the like.

When it is desired to increase the vertical position of the platformwith respect to the telescoping lifting members, extending elements maybe interposed between the nipple 84 and the extremity 80, as desired.

Reference is next made to FIGURES 2 and 3 for a description of anadjustable brace means which may be employed in order to more rigidlyand securely position the scalfold upon uneven flooring and the like.For this purpose, there is attached to one of the leg assemblies 1 apair of braces. Each brace consists of a curved leg 90 having a footmember 92 at its lower end adapted to engage upon the floor or othersurface, and at its upper end being pivoted, as at 94, to a collar 96which rotatably encircles one of the uprights 14 of a leg assemblybetween a pair of the rungs thereof. The leg is thus pivoted to the endassembly for vertically pivoting movement with respect thereto.

At the lower portion of that upright of the leg assembly, there isprovided a second sleeve or collar 97 to which is pivoted a lever 98 atone extremity as by a pivot pin or pins 100. The other end of this leveris pivoted, as at 102 to one end of a connecting link 104 whose otherend is pivoted, as at 106-, to the leg 90. A crank arm 108 is secured tothe lever 98 in rigid relation so that upon actuation of the crank arm,the lever 98 will be pivoted between the positions of FIGURES 2. and 3,and through the associated connecting link will thus pivotally raise orlower the leg 90. In FIGURE 2, the leg is shown in its lowered orbracing position, while in FIGURE 3, it is shown in its raised position.

Referring now to FIGURE 3, it will be seen that a tension spring 110 isconnected to the collar 97 and to the lever arm or crank 108 foryieldingly urging the latter into its lowered position, and thus throughthe link 104 pivot the leg 90 into its raised or inoperative position. Aflexible cable or the like 112 is attached to the outer end of the arm108 and is provided with a hook 114 which is positioned at the upperportion of the base. By means of this hook, the lever arm or crank maybe raised, thereby causing the lever 98 and link 104 to pivot the leg 90into its lowered position. The spring 110 will tend to raise the leg 90,as shown in FIGURE 3.

It will thus be seen that the brace means can be raised or lowered byremote control by the worker from the upper portion of the base of thescalfold.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly, all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. An adjustable portable scaffold comprising, a base consisting of apair of detachable leg assemblies having supporting casters anddetachable connecting means rigidly uniting the upper ends of said legassemblies, a platform and lifting means operatively secured to saidbase, connecting means and platform for adjustably elevating the latter.

2. An adjustable scaffold comprising, a base consisting of a pair of legassemblies and connecting means rigidly uniting said leg assemblies, aplatform, lifting means operatively secured to said base and platformfor adjustably elevating the latter, said leg assemblies each includinga socket at their upper ends, said connecting means including a beamhaving a flange engaging a side of the leg assemblies and projections onsaid beam detachably seated in said sockets.

3. The combination of claim 1 wherein said leg assemblies each include asocket at their upper ends, said connecting means including a beamhaving a flange engaging a side of each leg assembly and projections onsaid beam seated in said sockets, said lifting means being carried bysaid beam.

4. The combination of claim 1 wherein said lifting means includesrelatively slidable vertically telescoping elements, means fixedlysecuring said platform to one of said elements, means mounting the otherelement to said base, operating means carried by one of said elementsand operatively connected to both of said elements for causing adjustedvertical movement thereof, one of said elements having a vertical guideslot and the other eleslot.

5. The combination of claim 1 wherein said lifting means includesrelatively slidable vertically telescoping elements, means fixedlysecuring said platform to one of said elements, means mounting the otherelement to said base, operating means carried by one of said elementsand operatively connected to both of said elements for causing adjustedvertical movement thereof, one of said elements having a vertical guideslot, the other element having a member slidingly engaged in said guideslot and said operating means being attached to said member.

6. The combination of claim 1 wherein said lifting means includesrelatively slidable vertically telescoping elements, means fixedlysecuring said platform to one of said elements, means mounting the otherelement to said base, operating means carried by one of said elementsand operatively connected to both of said elements for caus ing adjustedvertical movement thereof, one of said elements having a vertical guideslot, the other element having a member slidingly engaged in said guideslot and inclined guide surfaces convergent upon the open end of saidguide slot.

7. The combination of claim 1 including a brace comprising a leg havinga foot at its lower end for engagement with a surface upon which saidbase rests, means pivotally mounting the upper end of the leg to the legassembly for veitical pivoting movement between a raised position and alowered surface engaging position and means for actuating said leg.

8. The combination of claim 1 including a brace comprising a leg havinga foot at its lower end for engagement with a surface upon which saidbase rests, means pivotally mounting the upper end of the leg to the legassembly for vertical pivoting movement between a raised position and alowered surface engaging position, means for actuating said leg, saidactuating means including a link connected to said leg and an actuatorfor operating said link.

9. The combination of claim 1 including a brace comprising a leg havinga foot at its lower end for engagement with a surface upon which saidbase rests, means pivotally mounting the upper end of the leg to the legassembly for vertical pivoting movement between a raised position and alowered surface engaging position, means for actuating said leg, saidactuating means including a link connected to said leg, an actuator foroperating said and said actuator including a member operable from theupper end of said base.

10. The combination of claim 1 including a brace com prising a leghaving a foot at its lower end for engagement with a surface upon whichsaid base rests, means pivotally mounting the upper end of the leg tothe leg assembly for vertical pivoting movement between a raisedposition and a lowered surface engaging position, means for actuatingsaid leg, said actuating means including a link connected to said leg,an actuator for operating said link, said actuator including a memberoperable from the upper end of said base, a lever pivotally mounted onsaid base and said link and said member being attached to said lever.

11. The combination of claim 1 including a brace com prising a leghaving a foot at its lower end for engagement with a surface upon whichsaid base rests, means pivotally mounting the upper end of the leg tothe leg assembly for vertical pivoting movement between a raisedposition and a lowered surface engaging position, means for actuatingsaid leg, a pair of collars mounted upon said leg assembly for rotatingsaid leg and said actuating means being secured to said collars, wherebysaid brace may be folded fiat against the leg assembly.

References Cited in the file of this patent UNITED STATES PATENTS208,852 Roadell Oct. 8, 1878 936,219 Coplinky Oct. 5, 1909 1,271,557Forsyth July 9, 1918 1,759,424 Strauss May 20, 1930 1,804,299 YentschMay 5, 1931 2,316,952 Halferty Apr. 20, 1943 2,378,984 Couture June 26,1945 2,419,065 Fowler Apr. 15, 1947 2,463,381 Hicks Mar. 1, 19492,593,386 Dirks Aug. 15, 1952 2,619,390 Johnson Nov. 25, 1952 2,672,319Nelson Mar. 16, 1954 FOREIGN PATENTS 128,570 Australia July 30, 1948843,154 Germany May 15, 1942

